Ore flotation employing ion exchange materials



Patented June 19, 1951 ORE FLOTATION EMPLOYING ION EXCHANGE MATERIALS Wayne 0. Hazen, Columbus, Ohio, assignor to Battelle Memorial Institute, Columbus, Ohio, a

corporation of Ohio No Drawing. Application Junezs, 1946, Serial No. 680,081

3 Claims. (01. 209-166)" This invention relates to reagents for and methods of treating ore particles in such a manner as to achieve greater selectivity in the flotation thereof.

It is .a customary procedure in ore flotation processes to employ collectors which become selectively attached to certain mineral particles, thereby making these particles water repellent, or air avid, so that they will attach themselves to air bubbles and be floated during the flotation process. The efliciency of most flotation processes depends largely upon the selectivity of the collectors, that is, the extent to which the collector attaches to the particles to be floated as well as the extent to which it does not attach to the particles not to be floated.

2 from solution and replacing them with nontoxic ions.

It has been found that almost all ore particles have some adsorbed ions upon their surfaces which, in certain cases, may be toxic or detrimental to effective selectivity in the flotation process. Apparently, these toxic ions may react with the flotation agents, such as collectors, to form water repellent compounds .whichybecause of their attachment to some particle, cause that particle to be floated. This type of detri- Increased selectivity is often obtained by employing an activator or depressant in conjunction with the collector. Activators facilitate attachment of the collector to the ore particles to be floated, whereas depressants prevent attachment of collector to particles not to be floated. Certain reagents of these types are valuable additions in specific flotation processes, but the same reagents are not applicable to flotation processes in general. Furthermore,

there are several flotation processes for which noefiective activator or depressants are known.

It is an object of the present invention to provide reagents for and methods of obtaining improved selectivity in flotation processes.

Another object of the invention is to provide a method of treating ores to inhibit the attachment of the collector to certain classes of particles contained therein during flotation.

Still another object of this invention is to provide a method of selectively floating an increased amount of the valuable constituents in ores.

A further object of this invention is to provide reagents which are generally applicable for obtaining increased selectivity in flotation processes.

Other objects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description thereof.

In general, the present invention relates to reagents for and methods of treating ore particles to obtain greater selectivity in the flotation thereof, which comprise subjecting the ore particles to the action of ion-exchange materials in the active form. The term active form, as used in the specification and claims, attached hereto, designates that form in which the ion-exchange material has the capacity for removing toxic ions mental effect is especially noticeablein soap flotation of ores. Toxic ions may also preventattachment of collectors to certain types of mineral particles. I

The present invention, which comprises removing these toxic ions, marks a clear departure fromthe practices of theprior art in which additional agents were used to provide ions intended to attach to the surfaces of the particles to be treated .so as to overcome the eflect exerted by the toxic ions. While no. positive proof of the exact mechanism by v which the ion-exchange materials function to increase selectivity, in flotation processes is at present available, the general thecry of this mechanism is fairly well developed and is borne out by all data available to date.

The ions on the surfaces of particles placed in a solution are in equilibrium with the same ions which are in solution. Removal of ions from the solution disturbs this equilibrium, causing the ions to leave the'su'rfaces of the ore particles in an effort to maintain equilibrium. Ion-exchange materials, as the name implies, remove certain ions from solution and replace them with other ions, such as the replacement of calcium with sodium ions. When an ion-exchange material is placed in the solution along with the ore particles, it removes the toxic ions from solution and replaces them with nontoxic ions. As above pointed out, this is a continuous action and as a result, the ions are being continually removed from the'surfacesof the ore particles. A particular example illustrating this mechanism is the removal of calcium ions, which are toxic ions in a soap flotation because they form insoluble, water-repellent compounds with soaps. It is readily apparent that the use of an ion exchanger to adsorb the calcium ions and replace them with sodium ions would soon remove the calcium ions from the surfaces of the ore particles. Consequently, the gangue, which in the case of iron ore flotation consists principally of quartz, would notbe coated by the flotation collector and would remain in the tailing because asszsu no calcium-soap compounds would form on the gangue particles to cause them to float. The removal of these ions. which react with the collectors to form compounds capable of acting as bridges between the collectors and the ore particles not desired to be floated. enhances the selectivity of the collectors so that collectors which have low selectivity under normal conditions, but which are quite cheap, may be successfully employed and the flotation process carried out more economically because of this factor.

Ion-exchange materials may be advantageously used, in general, to treat ore particles in flotation processes where selectivity in the flotation process is impaired by ions adsorbed upon the surfaces of the ore particles. The particular ionexchange material adopted for any-particular'flotation process will depend upon the ability of that ion-exchange material to remove the toxic ions from the given ore. There are two major types of ion-exchange materials, namely, cation exchangers and anion exchangers. It appears, however, that by far the greater number of toxic ions are cations rather than anions, so that cation-exchange materials have a much greater field of use in the flotation art. Anion exchangers, however, may be employed in those instances where toxicanions are to be removed and where anion exchangers may be found which will not detrimentally aflect other flotation agents.

The present invention is not limited to any particular type of flotation, but, of the three types of flotation collectors in wide use at present, namely, xanthates, amines, and soaps, the greatest applicability apparently lies in the flelds of soap flotation and xanthate flotation. Certain collectors commonly employed in soap flotation processes, such as the fatty acids (olelc. palmitic, stearic, myristic, linoleic) naphthenic acids, and tall oils, are especially suitable for use in combination with cation-exchange materials. The buffering eflect of the ion-exchange materials maintains a pH value particularly advantageous for soap flotations. Other types of collectors, such as xanthates, are quite satisfactory when employed to float ores such as copper sulflde and the like.

Various types of ores, such as iron ores, phosphate ores, copper ores, etc., have been successfully treated according to the present invention, which is applicable generally to any ore having toxic ions.

The normal flotation process includes the steps of grinding the raw ore to a particle size which gives desired mineral liberation, conditioning the ore particles in the presence of certain flotation agents, and air through the pulp to float out a preselected portion of the ore.

The ion-exchange material may be added to the pulp at any point in the flotation process, as long as the ore is subjected to treatment therethe actual flotation of the ore. The process is eifective whether the granular form or powdered form of ion exchanger is used. The ion-exchange material may be added directly to the pulp, or it may be held within a basket or other porous container to facilitate the recovery of the ion exchanger after it has become exhausted. Regeneration of the ion-exchange material is highly desirable, because this material is generally too costly to discard after a single use. Consequently, these procedures are usually preferred which provide for simple methods of recovering the ion exchanger.

In order to more specifically describe the present invention and to more clearly illustrate it, the following examples have been included:

mMPLEl A Mesabi taconite, consisting chiefly of hematite and magnetite as iron-bearing materials and containing quartz as the principal component of the g'angue, was ground to approximately 150 1 mesh at 50 per cent solids with distilled water in a steel ball mill. At this grind the liberation of the iron-bearing minerals from the gangue is approximately 90 per cent complete. The ground ore was then floated using cottonseed soap stock as a collector.

EXAMPLE 2 In this example the procedure was identical with Example 1 with the exception that 30 pounds per ton of ore of an ion-exchange material, comprising a sulphonated coal reagent sold under the name of Zeo Karb" by the Permutit Company, were added in the sodium form to the are charged into the ball mill.

EXAMPLE 3 An ion-exchange material, comprising a synthetic alumino-silicate gel sold under the name of fDoucil by the American Doucil Company, was added in the sodium or active form to the ground are in an agitator and agitated for a period-of one hour. The amount of exchanger added was equal to approximately 60 pounds per ton of ore. Following the conditioning of the ore, the pulp was floated using an emulsion of oleic acid and sodium oleate as the collector.

EXAMPLE4 by for a given minimum period of time prior to ples 1 to4 are given inTable 1;

Table 1 Ion-Exehangsllatrial Cmcentrate Telling No. Amount, Assay Dist. Army Dist.

Type Lbs/Ton Fe. Fe, Fe, Fe,

of Ore Per Cent Pu- Cent Per Cent Per Cent None 44. 5 6L6 2i. 1 35.4 coal N 54. 7 78. 5 l3. 5 2i. 8 Synthetic aluminodlimte gd. 0) 61.0 N. 0 ll. 4 no mierelin. C) 57.0 68.9 11.2 31.1

It is evidentfrom .Table 1 thatthe higher rades of concentrate (assay Fe, and increased recoveries of iron (dist. Fe, obtained by employing ion-exchange materials indicate an increased selectivity resulting from the use of these materials. The amount of ion-exchange material necessary to obtain the most beneficial results will vary from one ore to another and from one ion-exchange material to another, but Table 1 indicates. thatapproximately 60 pounds per ton should give a satisfactory result with several of the ion-exchange materials. This amount of ion exchanger is a-little high, but it may be separated and regenerated for future use soas to make the process economical. For example. an ion exchanger, of the synthetic organic resin type, was regenerated and reused twelve times without, showing any decrease in its effect upon the flotation efliciency.

Where the ion-exchange material is retained within a basket, of course, no separation step is Y required, and regeneration of the ion exchanger may be repeated frequently and easily. Smaller amounts of more active ion-exchange materials might be used, however, with suflicient economy to permit discarding after a single use.

Examples 1 to 4 represent tests made using diiferent ion-exchange materials on a given iron ore. In order to. compare the results of the same ion-exchange material upon a diiferent iron ore, a test was run in which a sample of iron ore designated as formation material from the Marquette range, consisting essentially of hematite and quartz, was ground for 20 minutes in a steel ball mill at 50 per cent solids with distilled water and floated in the usual manner using cottonseed soap stock as collector. A duplicate sample was ground as above with the addition of the same sulphonated coal ion-exchange material used in Example 2 present in the amount approximately 80 pounds per ton of ore. The re- Table 2 shows, therefore, that by usingan ion exchanger the flotation process canbe; prolonged until half again as much iron is flotated without materially afiectingthe grade of the concentrate, a further indication of increased selectivity.

The following examples disclosed the use of ion-exchange materials in the treatment of phosphate rock.

EXAMPLE '5 A 500-gram sample of Florida phosphate rock containing quartz and some clay as the principal gangue constituents was ground in a ball mill to minus 65 mesh and floated with oleic acid-sodium oleate emulsion collector inlthe absence of any cationic exchanger. v

EXAMPLE 6 This example was identical with Example 5,

'with the exception that the pulp was agitated with 25 grams of the same sulphonated coal ionexchange material in the sodium form used in Example 2 for 30 minutes prior to theaddition of the collector and flotation.

The results of Examples 5 and 6 are Table 3 below:

The high percentage of bone phosphate of lime (B. P. L. in the concentrate, as well as the increased percentage of the total bone phosphate shown in of lime recovered from the ore (dis. are fur-, ther illustrations of the increased selectivity in the flotation process obtained by employing ionexchange materials. I

Another type of ore to which the present invention has been applied with significant success is a copper sulfide ore containing a small amount of copper oxide. The procedure followed in obtaining the data shown in the following Table 4 was substantially the same as that described in Example 1. Potassium amyl xanthate was the collector employed and a synthetic alumino silicate formed the ion-exchange material.

Table 3 Ion-Exchange Material I Agitation Concentrate Tailing Amount Assay Dist. Assa Dist.

Type Lbs/Ton 5%: B. P. L., B. P. L., B. P. B.- P. L

of Ore Per Cent Per Cent Per Cent Per Cent None 10 57. 2 24. s 41. 1 75.1 sulphonated coaL. 100 30 69. 5 79. 5 27. 6 20. 5

sults of these tests are tabulated in Table 2 below: Table 4 Table 2 Without Ion Ex- With Ion Exchanger changer Ion-Exchange Material Concentrate Tailing OASS%Y CDisIt. CA ssg y CDisIt Amount Assay Dist. Assay Dist. er )er at or Type Lbs. [Ton Fe, Per Fe, Per Fe, Pcr Fe, Per Cent (out Cent of Ore Cent ent Cent Cent 30 Concentrate 25. 7 57. 5 26.65 81. 9 None 52 3 5 0 3L 2 4L 9 'DMHHES 0- 2 42- 5 23 1 sulphonated coal-.. 80 51. 6 87.0 15. 2 13.0

' Assay of heads=l.21% Cu.

In this particular ore, the gangue does not float and the problemlies in floating the copper-containing materials. The above Table 4 shows that 81.9 per cent of the total copperwas floated when the ion exchanger was used, as compared with only 57.5 per cent when no ion exchanger is used.

It is apparent from the above-detailed description thereof that the present invention comprises increasing the selectivity of ore flotation processes by treating the ore with an ion-exchange material. By practicing the present invention, higher grade concentrates as well as greater yields of the valuable constituents in the ores may be obtained.

Variations and modifications of the invention as hereinabove set forth will become apparent to those skilled in the art, and such changes as may be made without departing from the spirit of the invention as defined in the appended claims are to beincluded as part of this invention. For example, a mixture of ion-exchange materials may be used, as well as a single ion-exchange material.

What is claimed is:

1. The method of treating taconite ores consisting principally of quartz gangue materials and iron ore compounds comprising the steps of introducing a fatty acid collector, forming the compounds into a pulp in which some of the ore particles have adsorbed cations which repel the collector, introducing into the pulp solution an insoluble exchange reagent selected from the group consisting of sulphonated coal, synthetic aluminu- 8 ore particles thereby removing thecollector inhibiting cation from solution and then subjecting the pulp to froth flotation 3. The method of treating copper sulfide ores consisting principally of quartz gangue material and copper compounds comprising the steps of introducing an xanthate collector, forming the Y to froth flotation.

silicate gel and synthetic organic resin having more aillnity for the adsorbed cations on the adsorbing ore particles than have the ore particles thereby removing the collector inhibiting cation from solution, and then subjecting the pulp to froth flotation.

2. The method of treating phosphate rock consisting principally of quartz and clay gangue materials and phosphate compounds comprisin the steps of introducing a fatty acid collector, forming the compounds into a pulp in which some of the ore particles have adsorbed cations which repel the collector, introducing into the pulp solution an insoluble exchange reagent selected from the group consisting of sulphonated coal, synthetic alumino-silicate gel and synthetic organic resin having more afllnity for the adsorbed cations on the adsorbing ore particles than have the WAYNE C. HAZEN.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 1,325,817 Van Arsdale et al. Dec. 23, 1919 1,326,855 Edser Dec. 30, 1919 2,019,306 Handy Oct. 29, 1935 2,040,187 Rose May 12, 1936 2,161,010 Breerwood et al June 6, 1939 2,162,525 Breerwood June 13, 1939 2,187,930 Brown Jan. 23, 1940 2,349,637 Ruckwardt May 23, 1944 2,378,552 Hoag June 19, 1945 2,367,122 Hoag Jan. 9, 1945 2,414,199 Gutzett Jan. 14, 1947 2,470,150 De Vaney May 17, 1949 

1. THE METHOD OF TREATING TACONITE ORES CONSISTING PRINCIPALLY OF QUARTZ GANGUE MATERIALS AND IRON ORE COMPOUNDS COMPRISING THE STEPS OF INTRODUCING A FATTY ACID COLLECTOR, FORMING THE COMPOUNDS INTO A PULP IN WHICH SOME OF THE ORE PARTICLES HAVE ABSORBED CATIONS WHICH REPEL THE COLLECTOR, INTRODUCING INTO THE PULP SOLUTION AN INSOLUBLE EXCHANGE REAGENT SELECTED FROM THE GROUP CONSISTING OF SULPHONATED COAL, SYNTHETIC ALUMINOSILICATE GEL AND SYNTHETIC ORGANIC RESIN HAVING MORE AFFINITY FOR THE ADSORBED CATIONS ON THE ADSORBING ORE PARTICLES THAN HAVE THE ORE PARTICLES THEREBY REMOVING THE COLLECTOR INHIBITING CATION FROM SOLUTION, AND THEN SUBJECTING THE PULP TO FROTH FLOTATION. 